Second, humans are now a dominant driver of the climate and are very likely to be responsible for most of the recent warming we have experienced.

And future warming over the 21st century will likely be several degrees.

While a few degrees may not sound like a lot of warming, changes in the global average temperature this large have, in the past, been associated with very large and significant changes in the climate (for example, the last ice age was only about 10 degrees Farenheit colder than today).

In fact, one could argue that climate science has not significantly changed since it was first hypothesized that combustion of fossil fuels could change the climate — in 1896.

That's why, of the dozens of atmospheric scientists in our state at Texas A&M, University of Texas, Rice, Texas Tech, University of Houston, etc., approximately zero of them are skeptical of this mainstream view of climate science.

For example, if you are skeptical of the science of climate change, then you almost certainly oppose the Affordable Care Act, also known as Obamacare, and support gun rights.

Those who support action to reduce greenhouse gases very likely hold the opposite views.

If arguments about the science of climate change were actually about the science, then this result would make no sense. Whether climate change is true or not is a scientific matter, and it should be uncorrelated with philosophical views on the role of government in health care or the constitutional right to own a firearm.

But they are correlated. And this tells us that the arguments about the science of climate change are not actually about science.

So what is the argument about? The answer is policy.

If climate change is true and we decide to reduce emissions, then it will almost certainly require intervention by the government into the energy market. For some, that idea is so repugnant that the only conclusion is that the problem must not exist.

It is also about being part of the tribe. Climate change has achieved such an elevated status in the policy debate that it has become a litmus test. To be a Republican, for example, you must reject the science.

Any Republican who does not risks being voted out of office — as happened, for example, to Rep. Bob Inglis. (www.pbs.org/wgbh/pages/ frontline/environment/climate- of-doubt/bob-inglis-climate- change-and-the-republican- party/).

As proud Texans, we are sympathetic to those who worry about out-of-control eco-totalitarianism. And we both love cheap and abundant energy and the lifestyle it allows us to lead. But, like most people, Republican and Democrat alike, we also want to protect the environment. Thus, we both support balanced action to address the clear and present danger of climate change.

And the Montreal Protocol, which phased out ozone-depleting chemicals, was a profoundly cost-effective policy that saved the ozone layer.

Prior to implementation of both policies, it was argued that these regulations would bankrupt us and cause a litany of other terrible consequences — for example, forcing middle-class families to give up their air conditioners.

These predictions obviously turned out to be wrong. And today, many of those same people are arguing that regulations on greenhouse gases will bankrupt us and force us to give up cheap energy.

These people are, in fact, the true alarmists in the climate debate.

Throughout history, American ingenuity has overwhelmed every problem we've faced. Along the way, we have found cost-effective ways to clean up the air and switch off ozone-depleting substances. This not only led to a cleaner environment but to economic growth. And we are confident that the same thing will happen here.

If we put our minds to it, we can solve the climate problem and prosper along the way.

Only someone profoundly pessimistic would bet against American ingenuity.

Gerald R. North is the Distinguished Professor of atmospheric sciences at Texas A&M. Andrew E. Dressler is a professor of atmospheric sciences at Texas A&M.